[geeks] Best Vista story I've seen

[Francois Dion]

On 2/20/07, Lionel Peterson <lionel4287 at verizon.net> wrote:
> On Mon, 2007-02-19 at 21:11, Joshua Boyd wrote:
> > On Mon, Feb 19, 2007 at 08:52:07PM -0500, Charles Shannon Hendrix wrote:
> >
> > > I also heard that a lot of Vista sound drivers are unaccelerated, which seems
> > > to jive with previous Microsoft statements about not supporting accelerated
> > > sound hardware.
> >
> > Interestingly, DirectSound3D support is dropped.  Also dropped is
> > hardware mixing for DirectSound.  However, OpenAL drivers can still
> > accellerate whatever they want to, so games that chose to use OpenAL (a
> > cross platform standard, prefered by Apple and supported on Linux) will
> > still get accelerated sound.
>
> Maybe I'm just being dense, but what, exactly is an accelerated sound
> driver?
>
> Lionel

The best example ever is the Gravis Ultrasound. The GF1 chip had
independant access to memory on the card and so you could assign each
channel it's own memory buffer (actually, multiple buffers was). Even
at 32 channels, all you had to do to play 32 streams, was to feed the
buffers. The card did the frequency conversion, panning and the volume
(and a few other things), then mixed the channels into a stereo pair.
That is why the GUS was popular with the demo scene. It left all your
cpu cycles to do math and video.

So hardware mixing is the most common use of "accelerated" support.
The vast majority of games nowadays however simply use wav mixing for
sound effects, the music is all CD audio. That's a shame because the
music is no longer interactive. If all you are doing is mixing a few
sound effects, there is no need for hardware mixing, that is just
trivial to do.

Francois